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Title: | Role of the reactive atmosphere during the sol-gel synthesis on the enhancing of the emission quantum yield of urea cross-linked tripodal siloxane-based hybrids |
Author: | Freitas, Vania T. Lima, P. P. Ferreira, R. A. S. Carlos, L. D. Pecoraro, E. Ribeiro, S. J. L. de Zea Bermudez, V. |
Keywords: | ORGANIC-INORGANIC NANOCOMPOSITES CARBOXYLIC-ACID SOLVOLYSIS METAL ACTIVATOR IONS BRIDGED SILSESQUIOXANES ORGANIC/INORGANIC HYBRIDS LIGHT-EMISSION TUNABLE PHOTOLUMINESCENCE LAMELLAR STRUCTURE ENERGY-TRANSFER SILICA SPHERES |
Issue Date: | 2014 |
Publisher: | SPRINGER |
Abstract: | Transparent monoliths and films of urea cross-linked tripodal siloxane-based hybrids (named tri-ureasils) were prepared by the sol-gel process, under controlled atmosphere (inside a glove box) and ambient conditions and their structure and optical features were compared. X-ray diffraction data point out that all the materials are essentially amorphous and Si-29 NMR reveal an increase in the condensation degree (0.97) for the hybrids prepared under controlled atmosphere relatively to that found for those prepared under ambient conditions (0.84-0.91). The tri-ureasils are white light emitters under UV/Visible excitation (from 250 to 453 nm) being observed for the composites prepared inside the glove box a significant enhancement (60-80 %) of the absorption coefficient and higher emission quantum yield values (similar to 0.27 and similar to 0.20 for monoliths and films, respectively) relatively to those synthesized under ambient condition. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/20829 |
DOI: | 10.1007/s10971-013-3244-x |
ISSN: | 0928-0707 |
Publisher Version: | 10.1007/s10971-013-3244-x |
Appears in Collections: | CICECO - Artigos |
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